Simulation Study On Gas Permeation Performance Of Hybrid Polyimide Membrane

The problem of global warming is generally concerned home and abroad at present.Green less carbon becomes a way of life for people to pursue today.Separation of CO2 gas from the mixture of CO2/N2 is an important separation process in the energy and chemical industry,and the membrane separation process plays an important role in the recovery of CO2.Hybrid PI is made by doping inorganic phase into PI and the formation of the continuous system of membrane materials has good properties of organic and inorganic phases.It breaks through the bottleneck of the traditional research,development of organic membrane and inorganic membrane materials.To predict the properties of composite membranes and the gas diffusion performance has become a hot topic.Molecular simulation can reduce the development cycle of polymer membrane materials,reduce the cost of materials required for testing,improve efficiency and save development costs.The dissolution and diffusion of gas can not be interpreted and characterized from the free volume of polymer,the hydrogen bond between polymer and nanoparticle,adsorption energy and adsorption position,but the molecular simulation technology complements the shortcomings of the experiment.Using the MM,MD and GCMC method,the gas permeation properties of hybrid membranes were studied by using the PMDA-ODA as the unit,the SiO2 as the dopant and the COMPASS as the model.In order to construct a polymer chain with 20 monomers,a polymer chain model with similar experimental data is obtained by a series of optimization process.The S,D and P of CO2 and N2 in PI were obtained by molecular dynamics,and the X-ray was used to determine the structure of the polymer,and the hydrogen bond between the molecules and SiO2 was able to stabilize the particles.Through the calculation of free volume and other parameters,the permeability and separation performance of PI hybrid membranes is better than that of pure PI for CO2.